oskar mRN localization determines the formation of Drosophila pole cells and abdomen in the embryo. From previous project, we confirmed that the three components of Processing body (P-body), dDcp1, dDcp2 and dGe-1, are required for the proper oskar mRNA localization. This project is to further clarify how P-body components can work together with Dmoesin and regulate the anchorage of oskar mRNA.

Drosophila decapping protein 1, dDcp1, is a component of oskar mRNP complex and directs its proper posterior localization in the oocyte (Developmental Cell 10, 601–613 (2006)). However, the biological significance for the presence of dDcp1 in the oskar mRNP complex is not clear. Based on the mutations of two other P-body components, dDcp2 and Ge-1, we confirmed that both, again, affect oskar mRNP localization. Combining the localization of both dDcp2 and dGe-1along the cortical region and the intimate layer pattern at the posterior end in the oocyte, the formation of dDcp1-dGe-1-dDcp2 complex i n vitro and in vivo , and other genetic, cellular and biochemical evidences, we propose that dDcp2-dGe-1 complex stands by along the cortical region waiting for the arrival of dDcp1- oskar RNP. After dDcp2-dGe-1-dDcp1complex formation, oskar mRNP is localized at the posterior end in the oocyte.

Dmoesin is a membrane cytoskeletal cross-linker. Based on the physical interactions between dDcp2-F-actin and dDcp2-Dmoesin, we depict the scenario that F-actin-dDcp2-dGe-1 supports the location of dDcp1-o skar mRNP and the profound dDcp2-Dmoesin bonding anchors the oskar mRNP-dDcp1-dGe-1-dDcp2 complex deep in the posterior membrane of oocyte.

How Dmoesin regulates the anchorage of oskar mRNP through its interaction with P-body components is the aim of our future study. We expect to explore a new developmental function for P-body components and define the anchorage mechanism for oskar mRNP pending for almost 30 years.